ethyl 3-nitropropanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5-carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H) acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a mimimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro- 3,5-dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. The mixture is cooled The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted The combined extracts are dried over anhydrous magnesium sulfate filtered concentrated to yield an oil The mixture is filtered through filter aid concentrated to yield at reflux accompanied by removal of ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5-carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H) acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a mimimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro- 3,5-dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. the mixture is stirred one hour at room temperature The mixture is stirred 72 hours concentrated distilled

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2.43 g of ethyl 3-nitropropionate in 15 ml of absolute ethanol cooled using an ice bath, is added 20 mL of 1N sodium ethoxide in ethanol dropwise over 10 minutes keeping the temperature at 0-5° C. A slurry of 4-(2-chloroethoxy)-5-methoxyphthalaldehyde in 5 mL of ethanol is added. The ice bath is removed and the reaction allowed to warm to room temperature and stirred for 16 hours. The reaction is transferred to a beaker with 300 mL of water and neutralized with acetic acid to pH 4. The solid is collected and washed first with water, then with 40 mL of cold ethanol. The solid is dried to provide 2.48 g (70%) of ethyl 7-(2-chloroethoxy)-6-methoxy-3-nitro-2-naphthoate and ethyl 6-(2-chloroethoxy)-7-methoxy-3-nitro-2-naphthoate (1:1 mixture) as a yellow solid, m.p. 119-29° C. dec. at 0-5° C The ice bath is removed The solid is collected washed first with water The solid is dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 25 g (0.21 mole) of 3-nitropropionic acid, 300 mL of absolute ethanol and 10 drops of concentrated sulfuric acid is refluxed overnight. The reaction mixture is evaporated, and the residue partitioned between water and ether. The ether layer is washed with water, aqueous sodium bicarbonate solution and brine, then dried over sodium sulfate. The ether is removed in vacuo and the product distilled as a clear liquid to provide 21.54 g (69%) of Ethyl 3-nitropropionate as a clear oil, b.p. 160-165° C. at 120 mm Hg. is refluxed overnight The reaction mixture is evaporated the residue partitioned between water and ether The ether layer is washed with water, aqueous sodium bicarbonate solution and brine dried over sodium sulfate The ether is removed in vacuo the product distilled as a clear liquid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 25 g (0.21 mole) of 3-nitropropionic acid, 300 mL of absolute ethanol and 10 drops of concentrated sulfuric acid is refluxed overnight. The reaction mixture is evaporated, and the residue partitioned between water and ether. The ether layer is washed with water, aqueous sodium bicarbonate solution and brine, then dried over sodium sulfate. The ether is removed in vacuo and the product distilled as a clear liquid to provide 21.54 g (69%) of Ethyl 3-nitropropionate as a clear oil, b.p. 160-165° C. at 120 mm Hg. is refluxed overnight The reaction mixture is evaporated the residue partitioned between water and ether The ether layer is washed with water, aqueous sodium bicarbonate solution and brine dried over sodium sulfate The ether is removed in vacuo the product distilled as a clear liquid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3-nitro-propionic acid ethyl ester (16.25 g, 110.45 mmol, 4.0 equiv) in EtOH (150 ml) was added at 0° C. under an atmosphere of argon to a freshly prepared solution of sodium (2.54 g, 110.45 mmol, 4.0 equiv) in EtOH (110 ml). After 15 minutes, a solution of 3-methoxy-benzene-1,2-dicarbaldehyde (4.53 g, 27.61 mmol) in EtOH (150 ml) was added at 0° C. The reaction mixture was warmed to room temperature, and after 40 minutes, TLC analysis indicated complete conversion. 2 N aqueous HCl (55 ml, 4 equiv) was carefully added at 0° C., and the mixture was extracted with EtOAc (1.5 liter in total). The combined organic layers were washed with concentrated aqueous NH4Cl solution (200 ml), brine (400 ml), dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified via flash chromatography (gradient of toluene/hexane 5:5 to 10:0) to afford the title compound (0.942 g, 12%, inseparable 1:1.15 mixture of regioisomers A:B) as a yellow oil. 1H NMR (400 MHz, CDCl3): δ=8.87 (s, 1H isomer A), 8.69 (s, 1H isomer B), 8.33 (s, 1H isomer B), 8.15 (s, 1H isomer A), 7.64-7.59 (m, 1H isomer A+1H isomer B), 7.53 (d, J=8.1 Hz, 1H isomer B), 7.51 (d, J=8.3 Hz, 1H isomer A), 7.02 (d, J=6.5 Hz, 1H isomer B), 7.00 (d, J=7.8 Hz, 1H isomer A), 4.42 (q, J=7.3 Hz, 2H isomer A), 4.41 (q, J=7.1 Hz, 2H isomer B), 4.04 (s, 3H isomer A), 4.03 (s, 3H isomer B), 1.38 (t, J=6.3 Hz, 3H isomer A+3H isomer B). MS (ES+): 276 (M+H)+. after 40 minutes the mixture was extracted with EtOAc (1.5 liter in total) The combined organic layers were washed with concentrated aqueous NH4Cl solution (200 ml), brine (400 ml) dried over Na2SO4 filtered concentrated in vacuo The residue was purified via flash chromatography (gradient of toluene/hexane 5:5 to 10:0)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H)acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a minimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro-3,5 -dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. The mixture is cooled The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted The combined extracts are dried over anhydrous magnesium sulfate filtered concentrated to yield an oil The mixture is filtered through filter aid concentrated to yield at reflux accompanied by removal of ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H)acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a minimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro-3,5 -dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. the mixture is stirred one hour at room temperature The mixture is stirred 72 hours concentrated distilled

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H)acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a minimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro-3,5 -dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. the mixture is stirred one hour at room temperature The mixture is stirred 72 hours concentrated distilled

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5-carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H) acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a mimimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro- 3,5-dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. The mixture is cooled The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted The combined extracts are dried over anhydrous magnesium sulfate filtered concentrated to yield an oil The mixture is filtered through filter aid concentrated to yield at reflux accompanied by removal of ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5-carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H) acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a mimimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro- 3,5-dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. The mixture is cooled The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted The combined extracts are dried over anhydrous magnesium sulfate filtered concentrated to yield an oil The mixture is filtered through filter aid concentrated to yield at reflux accompanied by removal of ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A suspension of 116 g (0.97 mole) β-nitropropanoic acid (CAS number 504-88-1) in chloroform (1 l) is stirred and treated with 127.5 g (1.07 mole) thionyl chloride. A rapid evolution of gas takes place and the mixture is stirred one hour at room temperature. Ethanol (50 g, 1.07 mole) is added dropwise followed by rapid gas evolution. The mixture is stirred 72 hours, concentrated and distilled to yield ethyl β-nitropropanoate, bp 95°-105° C. at 15 mm. A solution of 182 g (1.84 mole) ethyl acrylate [CAS number 140-88-5] in t-butanol (150 ml) and 10 ml of Triton B is treated at 40° C. with 135.5 g (0.92 mole) of ethyl β-nitropropanoate. Additional portions of Triton B (2 ml×3) and ethyl acrylate (25 g×3) are added over a five-hour period. The mixture is cooled and poured into a solution of 100 ml of concentrated hydrochloric acid in water (1 l). The diethyl-γ-nitro-γ-carboethoxymethylpimelate is extracted using dichloromethane (4×500 ml). The combined extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated to yield an oil. The oil (160 g) is dissolved in ethanol (1.5 l) and treated with hydrogen in the presence of 7 g 20% Pd/C. The mixture is filtered through filter aid and concentrated to yield a mixture of 5-carboethoxyethyl-5-carboethoxymethyl-2-pyrrolidinone (major product), 5-carboethoxymethyl-5-carboxyethyl-2-pyrrolidinone, and 5-carboethoxyethyl-5-carboxymethyl-2-pyrrolidinone as an oil. The oil dissolved in 1 l of 50% ethanol is titrated with a solution of 50% sodium hydroxide with stirring at reflux accompanied by removal of ethanol. The hydrolyzed mixture is neutralized with concentrated hydrochloric acid to yield 5-carboxyethyl-5-carboxymethyl-2-pyrrolidinone in water. The water is removed at reduced pressure and the resulting solid is added to acetic anhydride (1 kg) with stirring. The mixture is heated at 100° C. for 16 hours. The mixture is filtered through filter aid and concentrated at reduced pressure to yield tetrahydro-3,5-dioxo-1H-pyrrolizine-7a(5H) acetic acid anhydride with acetic acid as an oil. The oil is dissolved in a mimimum amount of acetonitrile, an equivalent amount of water is added, and the mixture is stirred 16 hours. The mixture is concentrated at reduced pressure to yield a solid. The solid is recrystallized from acetonitrile to yield tetrahydro- 3,5-dioxo-1H-pyrrolizine-7a(5H)-acetic acid with a melting point of 177°-180° C. the mixture is stirred one hour at room temperature The mixture is stirred 72 hours concentrated distilled